問57
頻出度★★★
生体認証による入退室管理システムに全社員を登録し, 社内の各部屋に入室を許可する社員を設定した。退室は管理していない。a～dの記述のうち, この入退室管理システムで実現できることだけを全て挙げたものはどれか。 a 権限のある社員だけに入室を許可する。 b 入室者が部屋にいた時間を記録する。 c 入室を試みて, 拒否された社員を記録する。 d 部屋にいる人数を把握する。
平成26年度 秋期 ITパスポート試験 問57
This question's explanation and your answers so far.
解説
問 57
Incorrectア
a, b, c. Items a and c are correct, but b, “Record the time that an entrant stayed in the room,” is wrong. Time spent in a room is obtained as “exit time − entry time,” but this system does not manage exits, so no exit time exists. From entry records alone you cannot tell whether the employee left immediately or stayed all day, so ア, which includes b, does not qualify as an option that lists exactly all the achievable items.
- イ
正解 The correct answer is イ (a, c). This question asks how much information can be obtained from an entry/exit management system in which authentication takes place only when someone enters a room. Because the biometric data of all employees is registered and the employees permitted to enter each room have been configured, at the door of a room the system can identify “who this person is” by biometric authentication, check “whether this person is authorized to enter this room,” and thereby decide whether to unlock the door. Therefore a, “Permit only authorized employees to enter the room,” is exactly the central function of this system and can be achieved. In addition, when an employee without permission tries to enter, that person is still identified by biometric authentication and is then denied because the authorization check fails, so the system can keep an authentication log of “when, who, and at which room the entry was denied.” Therefore c, “Record employees who attempted to enter but were denied,” can also be achieved. On the other hand, neither b nor d can be calculated without information about leaving the room, and this system does not manage exits, so they cannot be achieved. Since only a and c can be achieved, the answer is イ, which lists exactly those items with nothing missing and nothing extra.
Incorrectウ
a, d. Item a is correct, but d, “Determine the number of people in the room,” is wrong. The number of people in a room is obtained as “number of people who entered − number of people who left,” but in this system, which does not record exits, you can only know the cumulative number of entrants and cannot calculate how many people are still in the room now. Moreover, ウ omits c, which is achievable, so it also fails the condition of listing all the items.
Incorrectエ
b, c, d. Item c is correct, but b and d are both pieces of information that presuppose exit records, so they cannot be achieved (b is the time spent in the room, d is the number of people in the room). Furthermore, this option does not include a, “Permit only authorized employees to enter the room,” which is the most basic function of this system, and that is wrong as well. It is a choice that contains two incorrect items and at the same time drops one correct item.
ここがポイント
- What information an entry/exit management system can provide is determined by where authentication events are recorded. In a configuration that manages entry only, you can judge whether entry is permitted, record who entered, and record denials (authentication failures), but you cannot obtain information such as time spent in a room or the number of people in a room, which requires a pair of entry and exit. Conversely, if you want to achieve these, you must also place an authentication device on the exit side and record entries and exits as pairs.
- As the three elements of access control, keep in mind identification / authentication, which determines who the person is; authorization, which decides whether that person has the right to do something; and accounting (audit trail) logging, which records who did what and when. In entry/exit management using biometric authentication, logging not only successful entries but also denied attempts is a prerequisite for detecting unauthorized entry and for countering piggybacking (tailgating).
用語